Russia as an aggressor has to pay a high price for the occupation of Crimea.

"Over the past two years, Crimea has seen mass arrests and repression. The rights of the Crimean Tatars are cynically violated. Occupants' behavior in Crimea is reminiscent of the Stalin era," the president stressed.

Poroshenko also says that both Ukraine and the international community continue to put pressure on the aggressor.

"Negotiations on the de-occupation of Crimea are underway based on various international formats, including the Geneva plus format. Russia will pay a due price as an aggressor. The whole world stands by Ukraine! Crimea is Ukraine!" the head of state summed up.